TEST: Improve BatchSimulate testing

[asoplata]

Currently, testing of BatchSimulate is very incomplete.

• Importantly, as @ntolley pointed out here ENH: Refactor BatchSimulate Example and Improve Documentation #857 (comment) , we need a way to test that the loky backend not only creates multiple workers, but actually uses the multiple parallel workers, in parallel. I think we may have to actually use loky directly in our tests for this (see ENH: Refactor BatchSimulate Example and Improve Documentation #857 (comment) ).

• The threading backend only has a single test, the multiprocessing and dask backends are not tested at all.

• Much of the testing is parameter TypeError testing, which is not testing BatchSimulate's functionality so much as it is testing _validate_type and _check_option. I hate to say it, but I think many of these tests can be removed. Relatedly, I will make an issue for introducing typing and type-checking for the codebase as a whole. I'm fine with leaving these tests in until we get more formal type-checking implemented, however.

• Relatedly, we should consider dropping the 'multiprocessing' backend as an option, since it has quirks in Joblib and, judging from joblib's documentation, is effectively replaced by loky (see https://joblib.readthedocs.io/en/stable/parallel.html#old-multiprocessing-backend ).

[samadpls]

Hi @asoplata , I agree with everything you've mentioned regarding the testing and using loky. I didn't add the Dask backend for testing, as this repo doesn't currently include it as a dependency, but if needed, it can be installed separately

[asoplata]

It's arguably hacky, but we could also try using psutil to track processes with specific names in our testing, ensuring that the appropriate number are created, etc.

[asoplata]

Hi @asoplata , I agree with everything you've mentioned regarding the testing and using loky. I didn't add the Dask backend for testing, as this repo doesn't currently include it as a dependency, but if needed, it can be installed separately

Thanks @samadpls , yes most of these BatchSimulation test refactors are TODO tasks that existed before your PR. We definitely appreciate your contributions!

[samadpls]

Thank you for the clarification! I will ensure it is useful and maintainable for future development. If you need any changes, please let me know. I'm happy to improve the structure and functionality.